BACKGROUND:
Early life events have been found to be associated with irritable bowel syndrome (IBS) suggesting a role in development of functional disorders. The study aim was to identify potential perinatal risk factors for adult IBS.

METHODS:
Utilizing a population-based nested case-control design, cases who met modified Rome III criteria for IBS and age- and-gender matched controls were identified using responses from prior mailed surveys to a random sample of Olmsted County residents. Medical records of eligible respondents were reviewed for perinatal events of interest. The association of early life events with subsequent case status was assessed using conditional logistic regression.

KEY RESULTS:
Of 3 417 respondents, 513 were born in Olmsted County and 108 met criteria for IBS. Due to missing records, 89 pairs were included in the final analyses. Logistic regression revealed only birth weight as a predictor of IBS. Lower birth weight increased the odds for IBS (OR = 1.54 [95% CI = (1.12, 2.08), p = 0.008]). Median birth weight was 3.35 kg (range: 1.96-5.24) and 3.57 kg (range: 2.18-4.59) for cases and controls, respectively. Maternal age, delivery method, and antibiotic exposure were not associated with IBS status but this study was only powered to detect large odds ratios.

CONCLUSIONS AND INFERENCES:
Lower birth weight was observed as a risk factor for IBS. It is not clear if in utero developmental delays directly lead to IBS or if low birth weight is a prospective marker for subsequent early life problems leading to IBS.